<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>

<script>
  Promise.all([
    new Promise((resolve, reject) => {
      $.ajax({
        url: 'url1',
        success: function (data) {
          resolve(data);
        }
      })
    }),
    new Promise((resolve, reject) => {
      $.ajax({
        url: 'url2',
        success: function (data) {
          resolve(data);
        }
      })
    })
  ]).then(result => {
    console.log(result);
  })
</script>

</body>
</html>